Camera control apparatus and method

ABSTRACT

For easy operation of switching a plurality of cameras, the cameras are arranged in juxtaposition such that the image-sensible range between the cameras partially overlap each other. A frame  36  indicative of a combined image-sensible range which includes an image-sensible range of each of the plurality of cameras is displayed on a monitor screen, and a frame  38  indicative of an image-sensing range of a selected camera is displayed in the frame  36  with a position and size corresponding to the direction and magnification of the image sensing. A sensed image of a corresponding camera is continuously displayed in the frame  38 . By moving the frame  38 , the image-sensing direction of the corresponding camera is controlled, and by enlarging/reducing the frame  38 , the magnification of the corresponding camera is controlled. When the frame  38  is moved to an image-sensible range of another camera, a camera subject to the control operation or image displaying is switched to another camera which corresponds to the new image-sensible range.

BACKGROUND OF THE INVENTION

Present invention relates to a camera control apparatus, and moreparticularly, to a camera control apparatus for controlling an imagesensing direction (panning/tilting) and a zooming ratio of a pluralityof cameras.

Conventionally, to remotely operate a video camera whose image sensingdirections (panning and tilting) and image sensing magnification ratio(zooming) are externally controllable, means such as operation leverwhich is rotatable along two axles, or push buttons, or buttonsdisplayed on an image display screen modeling after such lever or pushbuttons or the like are available. By utilizing such means, forinstance, a camera rotation angle or angle velocity is changed inaccordance with the operation of the lever, or camera rotation isrealized or a zooming ratio is changed while the button is depressed. Asa matter of course, absolute or relative angles of panning/tilting and azooming ratio may be designated by directly inputting a value.

In a case where a plurality of cameras are to be controlled by suchcamera control apparatus, camera operation means may be provided foreach of the plurality of cameras, or combination of camera selectionmeans for selecting a control-subject camera and camera operation meansfor operating the selected camera may be provided. When a large numberof cameras are to be controlled, the latter arrangement is moreadvantageous with respect to cost.

In remote control operation, a camera is operated by viewing an imagesensed by the camera in a monitor screen. In the conventional apparatus,no other information besides the image sensed by the subject camera (thecamera subjected to remote operation, or the camera whose sensed imageis to be viewed) is displayed on the monitor screen. Therefore, forinstance, if an operator wishes to direct a camera to an image outside apresent image-sensing range of the subject camera, the operator mustperform operation through trial and error to find the image of interest.

Although the image-sensible range of a camera is limited, in most cases,an operator is not informed of the image-sensible range of operatingcameras. Even if the operator is informed of the image-sensible range ofthe cameras, such information is indicated by values only e.g., anglesof the camera or the like, thus the operator cannot easily confirm theimage-sensible range on a monitor screen which performs remote controloperation. In addition, the operator cannot easily confirm the presentdirection of the camera within the image-sensible range.

Furthermore, in the case where a plurality of cameras are to be remotelyoperated, an appropriate camera must be first selected in accordancewith an operator's target position. Therefore, it is necessary todisplay information with respect to an image-sensing range of eachcamera in a user-friendly manner. Particularly in a case where a movingsubject is to be sensed by a plurality of video cameras arranged injuxtaposition so that an image-sensing view is continuous, an operatormust switch cameras to obtain a camera to be remote-controlled or whoseimage is to be displayed each time the subject image moves, and performnecessary control operation. Since such operation is quite complicated,there has been a demand for easier operation method.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the abovesituation, and has as its object to provide a camera control apparatuswhich solves the above problem.

Another object of the present invention is to provide a camera controlapparatus which enables easy camera switching and easy camera operationof a plurality of video cameras arranged in juxtaposition.

According to the present invention, a combined image-sensible range of aplurality of cameras is displayed in a monitor screen, and an area of animage-sensing range of a currently-selected camera which is locatedwithin the combined image-sensible range is displayed in the positionand the size corresponding to the image-sensing direction andimage-sensing magnification of the currently-selected camera. In theimage-sensing range of the selected camera, an image sensed by theselected camera is displayed continuously. Accordingly, an operator isable to confirm the image-sensing range of the selected camera withinthe entire image-sensible range of the plurality of cameras. Also, anoperator is able to perform control operation of a plurality of camerasas if he/she is operating only one camera.

Also, in a case where image sensing is performed by switching aplurality of cameras, following a subject moving from one camera'simage-sensible range to another camera's image-sensible range, anoperator is able to switch cameras by operating the image-sensing rangedisplayed by image-sensing-range display means. Accordingly,camera-switch operation becomes easy.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram showing a general structure of the firstembodiment;

FIG. 2 is a diagram showing an arrangement of cameras 10 a and 10 b usedin the present embodiment;

FIG. 3 shows a display screen of a monitor 18 according to the presentembodiment;

FIG. 4 shows another display screen of the monitor 18 according to thepresent embodiment;

FIG. 5 is a flowchart explaining operation according to the presentinvention;

FIG. 6 is a flowchart of panning/tilting instruction processingaccording to the present embodiment;

FIG. 7 shows a display screen of the monitor 18 when camera 10 a isselected according to the modified embodiment;

FIG. 8 shows a display screen of the monitor 18 when camera 10 b isselected according to the modified embodiment;

FIG. 9 is a flowchart of panning/tilting instruction processingaccording to the display method shown in FIGS. 7 and 8;

FIG. 10 is a view for explaining overall operation according to thethird embodiment;

FIG. 11 is a flowchart describing detailed processing of step S12 shownin FIG. 5 according to the third embodiment; and

FIG. 12 is an explanatory view showing an example of camera arrangementaccording to the third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described indetail in accordance with the accompanying drawings.

First Embodiment

FIG. 1 is a block diagram showing a general structure of the firstembodiment. Referring to FIG. 1, reference numeral 10 a and 10 b denotevideo cameras which are arranged in juxtaposition facing the samedirection and whose image-sensing direction (pan and tilt) and animage-sensing magnification ratio (zoom) are externally controllable;and 12, a camera control apparatus which controls the video cameras 10 aand 10 b to display images sensed by these cameras. The camera controlapparatus 12 is constructed with a personal computer or a work station.In the present embodiment, for the purpose of explanatory convenience,the two video cameras 10 a and 10 b are utilized. However, the presentinvention is also applicable to the case where more than three videocameras are utilized.

The camera control apparatus 12 includes: a CPU 14 which controls theentire apparatus; a memory 16 which stores control programs or controldata for the CPU 14, control values or the like for the video cameras 10a and 10 b, and image data derived from the video cameras 10 a and 10 b;an image monitor 18 which displays an image; image-sensing-directioninstruct means 20 which instructs the CPU 14 of an image-sensingdirection of the cameras 10 a and 10 b; zoom instruct means 22 whichinstructs the CPU 14 of an image-sensing magnification ratio of thecameras 10 a and 10 b; update instruct means 24 which instructs updatingof derived images in a combined image-sensible range in which all theimage-sensible range (field of view) of the cameras 10 a and 10 b iscombined; and confirmation instruct means 26 which instructs the CPU 14to confirm input of various instructions (e.g., instruction by theinstruct means 20, 22 and 24).

Reference numeral 28 denotes a camera interface for connecting videocameras 10 a and 10 b, where various camera control signals e.g.,panning, tilting or zooming values, are supplied to the cameras 10 a and10 b, or various video signals from the cameras 10 a and 10 b arereceived.

The devices 14 to 28 included in the camera control apparatus 12 areconnected to a system bus 29, and various data is transferred throughthe system bus 29.

FIG. 2 is a plan view showing an arrangement of the cameras 10 a and 10b. The cameras 10 a and 10 b are directed to the same direction in aninitial state, and are arranged in juxtaposition such that theimage-sensible range, which is an area sensible by panning, tilting orzooming a camera, partially overlap each other. The partially-overlappedimage-sensible range of the cameras 10 a and 10 b enables to assure awide camera view which cannot be attained by a single camera, without adead angle. More than two cameras may be arranged in juxtaposition, ormay be positioned side by side or on top of each other.

FIG. 3 shows a display screen of the image monitor 18 according to thepresent embodiment. The image monitor 18 may be an independent imagedisplay apparatus, or may be a single window in a window display system.Referring to FIG. 3, rectangular frames 30 a and 30 b indicated by thebroken lines show the positions of image-sensing optical axes at aboundary of pan/tilt of the cameras 10 a and 10 b, that is, the movableranges of image-sensing optical axes of the cameras 10 a and 10 b. Arectangular frames 32 a and 32 b surrounding the rectangular frames 30 aand 30 b respectively indicate the image-sensible range (or a field ofview) of the camera 10 a and 10 b. The rectangular frames 32 a and 32 bare the widest image-sensing range obtained when zooming is set at thewidest end (least magnification) at the boundary point of pan/tilt.

The rectangular frames 32 a and 32 b overlap each other in a portion 34indicated by hatching. That is, the hatched portion 34 is a field ofview overlapping area. A rectangular frame 36 including theimage-sensible ranges 32 a and 32 b of the cameras 10 a and 10 bindicates the combined image-sensible range (field of view) which can beobtained by combining the image-sensible ranges 32 a and 32 b. (Notethat in FIG. 3, the rectangular frame 36 is indicated by broken lines inthe outer portion of the rectangular frames 32 a and 32 b forillustrative convenience.) In other words, the field of view overlappingarea 34 is equivalent to a logical multiplication of the rectangularframes 32 a and 32 b, and the combined image-sensible range 36 isequivalent to a logical addition of the rectangular frames 32 a and 32b.

In order to display an image, sensed by a plurality of cameras arrangedin juxtaposition, without any awkward gap in movement of the displayedimage, it is preferable to arrange the cameras 10 a and 10 b such thatthe width of the field of view overlapping area 34 is larger than thewidth of the image-sensing range at the maximum wide angle (wide end) ofthe video cameras 10 a and 10 b.

A rectangular frame 38 indicated by the thick solid line denotes animage-sensing range of a currently-selected video camera (camera 10 a inFIG. 3), with the present panning angle, tilting angle and zoomingmagnification ratio. In FIG. 3, the video camera 10 a faces the centerof the image-sensible range of the camera 10 a and the zoomingmagnification ratio is set at the maximum wide angle (wide end).

The rectangular frame 40 indicates an image sensing range obtained in acase where the video camera 10 a is panned and tilted to the boundary ofthe upper right while the zooming is set at the maximum wide angle (wideend). The rectangular frame 42 indicates an image sensing range obtainedat the maximum telescopic angle (tele end). In other words, when thevideo camera 10 a is panned and tilted to the boundary of the upperright and zooming is set at the maximum wide angle (wide end), therectangular frame 38 indicative of current image-sensing range isdisplayed at the position of the rectangular frame 40. With the sameoptical axes of the video camera 10 aif zooming is set at the maximumtelescopic angle (tele end), the rectangular frame 38 is displayed atthe position of the rectangular frame 42.

Note that in the present embodiment, a current-selected camera, eitherthe cameras 10 a or 10 b, only needs to be managed within the controlapparatus, thus needs not be specifically informed to the operator. Inview of this, the rectangular frames 30 a, 30 b, 32 a, 32 b, and thefield of view overlapping area 34 need not be displayed on the screen ofthe image monitor 18. In other words, frames to be displayed on thescreen of the image monitor 18 are the rectangular frame 36 indicativeof the combined image-sensible range and the rectangular frame 38indicative of the current image-sensing range as shown in FIG. 4.

According to the present embodiment, an operator views an imagedisplayed in the rectangular frame 36 as if the image is the sensiblerange of a single camera. The camera switching operation necessary tochange an image-sensing direction is performed by the processing of thepresent control apparatus. The processing will be apparent from thefollowing description.

Operation of the present embodiment will now be described in detail withreference to FIGS. 5 and 6.

Images sensed in an entire image-sensible range of the cameras 10 a and10 b are displayed in the rectangular frame 36 indicative of thecombined image-sensible range (step S1). More specifically, zooming isset at wide end and each of the video cameras 10 a and 10 b are pannedand tilted from one side to the other side of the boundary of pan/tilt.A subject within the image-sensible ranges 32 a and 32 b is sequentiallysensed and stored in the memory 16. Then the sensed images are combinedto be displayed within the rectangular frame 36.

It is then controlled such that pan, tilt, and zoom values of the videocameras 10 a and 10 b are set at an initial setting condition (step S2).The initial setting condition is e.g., if a video camera 10 a isselected, the condition where the camera 10 a faces the center of theimage-sensible range 32 a and zooming is set at wide end. The conditionmay be arbitrarily set by an operator such that the camera faces thecenter of the combined image-sensible range 36.

Upon setting the initial setting (step S2), an image sensed by theselected camera 10 a (or camera 10 b) is derived and stored in thememory 16. In the combined image-sensible range 36, the rectangularframe 38 is overwritten with the size corresponding to the presentzooming ratio at a position corresponding to the present panning/tiltingposition of the selected camera 10 a (or camera 10 b). Then, the sensedimage is overwritten such that it fits in the rectangular frame 38 (stepS3).

Thereafter, in a case where no update request for updating an image ofthe maximum field of view is received (step S4) and no control requestof the video camera 10 is received (step S9), image sensing anddisplaying of the sensed image are repeated (step S3). Accordingly, thesensed image of the video camera 10 a (or camera 10 b) is displayed as amoving picture in the rectangular frame 38.

An update request in step S4 for updating an image of the maximum fieldof view is determined by whether or not the update instruct means 24receives an update input operation. The update request is input by,e.g., performing input operation which has been set as an updaterequest, by an input apparatus such as a pointing device e.g. a keyboard or mouse or the like.

In the case of receiving the update request (step S4), the currentconditions (panning angle, tilting angle, zooming value and the like) ofthe selected video camera 10 a (or camera 10 b) are stored (saved) inthe memory 16 (step S5). As similar to step S1, zooming is set at wideend and each of the video cameras 10 a and 10 b are panned and tiltedfrom one side to the other side of the boundary of pan/tilt. A subjectwithin the image-sensible ranges 32 a and 32 b is sequentially sensedand stored in the memory 16. Then the sensed images are combined to bedisplayed again in the rectangular frame 36 (step S6).

The condition of camera 10 a (or camera 10 b) is returned to the“selected” condition, and the setting (panning angle, tilting angle,zooming value) is returned to the conditions stored in step S5 (stepS7). Thereafter image sensing is performed, and the sensed image isstored in the memory 16. The rectangular frame 38 is then overwrittenwith a size corresponding to the present zooming ratio at a positioncorresponding to the present panning/tilting position of the camera 10 a(or camera 10 b). Thereafter, the sensed image is overwritten such thatit fits in the rectangular frame 38 (step S8). If no control request ofthe video cameras 10 a and 10 b is received (step S9), the processingreturns to step S3 and image sensing and displaying of the sensed imageis repeated.

The camera control request in step S9 is determined by whether or notthe image-sensing direction instruct means 20 or the zoom instruct means22 perform any input operation. The control request is also input byspecific input operation which has been set as an instruction request,by an input apparatus such as a pointing device e.g. a key board ormouse or the like. For instance, the rectangular frame 38 is moved bydragging the frame with a mouse (operation performed by moving thesubject while depressing a mouse button). In addition, the rectangularframe 38 is enlarged/reduced by operating a specific control spot on therectangular frame 38 with a mouse, as exemplified in a drawing softwareor the like, whereby controlling a zoom value of the correspondingcamera. By moving the rectangular frame 38 indicative of the currentimage-sensing range within the rectangular frame 36, an instruction canbe made to select the camera 10 a or 10 b as a control subject. When therectangular frame 38 is within the rectangular frame 32 a, the camera 10a is selected. When the rectangular frame 38 is within the rectangularframe 32 b, the camera 10 b is selected.

In response to a panning/tilting request, the amount of movement of therectangular frame 38 relative to the rectangular frame 32 a (or 32 b) isdetected, and the amount of pan/tilt for the camera 10 a (or camera 10b) is calculated (step S10). Detailed processing thereof is shown inFIG. 6.

First, a position of the rectangular frame 38 which has been moved isdetected (step S21). It then calculates where the detected position islocated, that is, which rectangular frame 32 a or 32 b indicative of theimage-sensible range of respective cameras 10 a and 10 b (step S22). Ifthe position is included in the rectangular frame 32 a, the camera 10 ais selected as the control-subject (step S23), otherwise the camera 10 bis selected as the control-subject (step S24). If the rectangular frame38 is included in the field of view overlapping area 34, a cameradetermined in accordance with a predetermined priority, or a cameraselected before the rectangular frame 38 is moved, becomes thecontrol-subject. The amount of pan/tilt for the camera 10 a (or 10 b) iscalculated on the basis of the relative position of the rectangularframe 38 with respect to the rectangular frame 32 a (or 32 b) indicativeof the image-sensible range of the control-subject camera 10 a (or 10 b)(step S25).

In response to a zooming request, the necessary zooming ratio iscalculated on the basis of the new size of the rectangular frame 38. Forinstance, the size of the rectangular frame 38 at wide end is comparedwith the size of the rectangular frame 38 at tele end, to calculate thezooming ratio corresponding to the new size (step S11).

In the present embodiment, the checking of whether or not there is anyinput instruction by the image-sensing-direction instruct means 20 andthe zoom instruct means 22 is executed sequentially; however, it may beexecuted asynchronous by an interruptive process or the like.

Next, the selected video camera 10 a (or 10 b) is controlled such thatthe camera is set in the conditions obtained in steps S10 and S11 (stepS12). Then with that setting, image sensing is performed and stored inthe memory 16. In the rectangular frame 36 indicative of the combinedimage-sensible range, the rectangular frame 38 indicative of the currentimage-sensing range is overwritten with a size corresponding to thezooming ratio at a position corresponding to the present panning/tiltingposition of the selected camera 10 a (or camera 10 b). Then, the sensedimage is overwritten such that it fits in the rectangular frame 38 (stepS13).

Note that when the panning angle or the tilting angle is changed, or thezooming value (magnification ratio) is increased, the position of therectangular frame 38 is changed, or the size of the rectangular frame 38is reduced. Therefore, with respect to an area displayed prior to thechange, the area stored in the memory 16 is displayed.

Whether or not the conditions of the selected camera 10 a (or 10 b) isdesired by an operator is determined by whether or not the confirmationinstruct means 26 receives any input operation (step S14). Theconfirmation instruction is also, similar to other instructions, inputby a specific operation of an input apparatus such as a pointing device,e.g. a key board or mouse or the like. The confirmation instruction maynot necessary be provided. More specifically, confirmation of theoperator may be determined by forthcoming input operation (e.g. cameracontrol request). When a camera control request is continuouslyinputted, the requests are sequentially processed. If confirmation isnot made, the processing returns to step S10 to repeat the cameracontrol request processing and image-sensing and displaying operation.

Note that in steps S10 and S11 in FIG. 5, the series of processing, thatis, from receiving a camera control request to displaying a sensed imageof a camera, can be adjusted by changing the response-time interval, oran amount of change in panning/tilting angles or a zooming value.(Herein, the response-time interval is the time necessary to startprocessing in response to an operator's instruction to changepanning/tilting angles or a zooming value.) If the response-timeinterval or the amount of change are set to a small value, it ispossible to make a small adjustment of a selected camera while viewingan image, however the load added to the camera control apparatus 12 ishigh. On the other hand, if the response-time interval or the amount ofchange are set to a large value, the small adjustment of the camera isdifficult. Thus, the image displayed on the screen moves awkwardly.However, the load added to the camera control apparatus 12 is low.

When it is determined that the camera condition is confirmed by anoperator (step S14), it is checked whether or not a terminateinstruction of the entire processing is issued (step S15). If it isissued, the processing ends, while if it is not issued, the processingreturns to step S3 to repeat the above described operation.

According to the present invention, the image-sensing field of view canbe practically enlarged by controlling a plurality of cameras, arrangedin juxtaposition so that the image-sensing field of view is continuous,in an integrated manner. In addition, the present invention realizeseasy camera operation by an operator so that the operator does not haveto deal with cumbersome switching operation of a plurality of cameras.In other words, the operator is able to perform pan/tilt/zoom operationas well as selection of a plurality of cameras by operating therectangular frame 38 only. The present embodiment is particularlyadvantageous in a case where image-sensing is performed by following asubject moving from one image-sensible range of a camera to anotherimage-sensible range of another camera, because the operator does notneed to perform selecting operation of a camera to be controlled or forimage sensing.

Second Embodiment

In the first embodiment, the entire combined image-sensible range(rectangular frame 36) is displayed in the monitor screen. However, oneof the rectangular frame 32 a or 32 b, indicative of the image-sensibleranges of respective cameras 10 a and 10 b, may be displayed in thescreen of the monitor 18. By displaying the rectangular frames 32 a and32 b, it is possible to display an image in the combined image-sensiblerange or a currently-sensing image in a larger size.

For instance, assuming that the camera 10 a is selected,the-image-sensible range of the camera 10 a is set as large as possiblewithin the display range 50 of the monitor 18 as shown in FIG. 7, and arectangular frame 52 a indicative of the image-sensible range of thecamera 10 a is displayed in the monitor 18. In the rectangular frame 52a, a rectangular frame 54 indicative of a current image-sensing range isdisplayed at a position corresponding to the present panning/tiltingangles, and with the size corresponding to the zooming ratio. FIG. 8shows a screen of the monitor 18 in a case where the camera 10 b isselected. The image-sensible range of the camera 10 b is set as large aspossible within the display range 50 of the monitor 18 as shown in FIG.8, and a rectangular frame 52 b indicative of the image-sensible rangeof the camera 10 b is displayed in the monitor 18. In the rectangularframe 52 b, a rectangular frame 54 indicative of a current image-sensingrange is displayed at a position corresponding to the presentpanning/tilting angles, and with the size corresponding to the zoomingratio. The rectangular frame 56 indicative of the combinedimage-sensible range is not displayed on the screen of the monitor 18.Note that the size of the display range 50, rectangular frames 52 a, 52b and 56 are exaggerated in the drawings for the illustrativeconvenience.

When cameras other than the currently-selected camera (camera 10 a inFIG. 7 and camera 10 b in FIG. 8) are present, the sides 58 a and 58 b(indicated by broken lines in FIGS. 7 and 8) of the rectangular frames52 a and 52 b are displayed in a different form than the other sides ofthe rectangular frames 52 a and 52 b, to indicate that the directionsadjacent to the sides 58 a and 58 b are image-sensible by other cameras.The sides may be displayed in a different color.

Referring to the displaying method shown in FIGS. 7 and 8, processing inresponse to a panning/tilting instruction will be described next. FIG. 9is a flowchart explaining the process.

First, a position of the rectangular frame 54 which has been moved isdetected (step S31). It is determined whether or not the position isoutside the rectangular frame 52 a (or 52 b), exceeding the adjacentcamera display side 58 a (or 58 b) of the rectangular frame 52 a whichis indicative of the image-sensible range of the currently-selectedcamera (step S32). In a case where the position does not exceed theadjacent camera display side 58 a (or 58 b) (step S32), thecontrol-subject camera is not changed (step S33). Meanwhile, in a casewhere the position exceeds the adjacent camera display side 58 a (or 58b) (step S32), the display screen of the monitor 18 is switched (stepS34) to a screen corresponding to the image-sensible range of theadjacent camera and the control-subject camera is changed (step S35).

Upon completion of step S33 or step S35, the amount of pan/tilt for thecontrol-subject camera 10 a is calculated (step S36) on the basis of therelative position of the rectangular frame 54 with respect to therectangular frame 52 a (or 52 b) indicative of the image-sensible rangeof the control subject camera 10 a (or 10 b).

By the processing described above with reference to FIGS. 7-9, a sensedimage of each camera and an image-sensible range of each camera can beviewed with a larger size although it would become difficult to confirm,with a single glance, the combined image-sensible range. The presentembodiment is particularly useful in a case where a predetermined screensize is small, or a case where a large number of cameras are utilized sothat a larger size or better resolution of an image is desired to bedisplayed in the rectangular frame indicative of the current conditionof the camera.

Third Embodiment

In the first and second embodiments, one of the two cameras iscontrolled, and the selected camera is controlled each time apanning/tilting angle or a zooming value is changed by operation of theframe 38 indicative of the current image-sensing range.

When the position or size of the frame 38 is changed within theimage-sensible range of one of the cameras, not many problems arise.However, when an instruction is given to move the frame 38 from theimage-sensible range of camera 10 a to the image-sensible range ofcamera 10 b, if the direction of optical axes or zooming value of thecamera 10 b is different from those of the camera 10 ait would take awhile to apply the conditions of the camera 10 a to the conditions ofthe camera 10 b. More specifically, assume that the frame 38 is locatedwithin the image-sensible range 32 a of the camera 10 a. If the frame 38is moved to the image-sensible range 32 b of the camera 10 b, exceedingthe field of view overlapping area 34, the displaying of the sensedimage may be slightly delayed, depending on the conditions of the camera10 b.

In view of the above, according to the third embodiment, while the frame38 indicative of the current image-sensing range is within theimage-sensible range 32 a and an operator performs control operation ofthe camera 10 athe camera 10 b is controlled such that a rectangularframe 38′, indicative of an image-sensing range of the camera 10 b, isalways in stand-by condition within the field of view overlapping area34, as shown in FIG. 10. More specifically, while the panning angle ofthe camera 10 b is fixed such that the frame 38′ always stays within thefield of view overlapping area 34, the tilting angle and zooming valueof the camera 10 b are changed along with changes in the tilting angleand zooming value of the camera 10 a which performs image sensing. Byvirtue of this, when the frame 38 is moved from the image-sensible range32 a of the camera 10 a to the field of view-overlapping area 34, thenmoved further to the image-sensible range 32 b of the camera 10 b, thecamera control is performed quickly without taking much time. Therefore,an operator is able to view natural motion of the subject image. Notethat the frame 38′ is not actually displayed.

In order to realize the above, the processing shown in FIG. 11 isperformed in step S12 of FIG. 5.

Note that in the following descriptions, a camera whose sensed image isdisplayed in the frame 38 will be referred to as a “control-subjectcamera,” and a camera corresponding to the frame 38′ which isstanding-by in the field of view overlapping area 34 will be referred toas a “non-sensing camera,” for the purpose of explanatory convenience.In a case where the camera 10 a is the control-subject camera, thecamera 10 b becomes non-sensing camera, or vice versa.

Referring to FIG. 11, in step S41, the control-subject camera iscontrolled in accordance with a panning angle, tilting angle and zoomingvalue determined in steps S10 and S11 of FIG. 5.

The processing proceeds to step S42 where the current direction ofnon-sensing camera is detected (e.g., cameras 10 a and 10 b have afunction which returns the current conditions in response to apredetermined request to send a current status, or the cameras alwaysstore the current conditions of each camera in a predetermined area ofthe memory 16) to determine whether or not the frame 38′ of thenon-sensing camera is within the field of view overlapping area 34. IfNO in step S42, the panning angle of the non-sensing camera iscontrolled in step S43 such that the frame 38′ is moved to the field ofview overlapping area 34, and the processing proceeds to step S44. IfYES in step S42, the processing in step S43 is skipped and theprocessing proceeds to step S44.

In step S44, the conditions of the non-sensing camera are controlledsuch that its tilting angle and zooming value are identical to those ofthe control-subject camera.

According to the above processing, assuming that the camera 10 a is thecontrol-subject camera, when the position or size of the frame 38 ischanged within the image-sensible range 32, the non-sensing camera canbe maintained in the state such that the non-sensing camera faces thefield of view overlapping area 34.

Note that in the first, second and third embodiments, descriptions havebeen provided for a case where two cameras are arranged in parallel,side by side; however the cameras may be arranged one on top of theother, or any other manner. Moreover, the number of cameras is notlimited to two, but may be three or more.

In the case where a plurality of cameras are parallelly arranged asshown in FIG. 2, a predetermined distance must be secured between thecameras so that the image-sensible ranges of the cameras partiallyoverlap each other. If the plurality of cameras are arranged as shown inFIG. 12 so that each of the cameras faces different directions, thedistance between the cameras is substantially ignored. In the case ofFIG. 12, an operator is able to perform camera control in 360° panningangle as if the operator is operating only a single camera.

In addition, in the foregoing embodiments, an example has been providedin a case where a plurality of cameras are connected to a single controlapparatus; however, the present invention is not limited to this. Forinstance, a network interface card may be included and the presentapparatus may serve as a camera server in a network. A client of theserver would perceive as if one camera is being shared on the cameraserver.

The present invention can be applied to a system constituted by aplurality of devices, or to an apparatus comprising a single device.Furthermore, the invention is applicable also to a case where theinvention is embodied by supplying a program to a system or apparatus.In this case, a storage medium, storing a program according to theinvention constitutes the invention. The system or apparatus installedwith the program read from the medium realizes the functions accordingto the invention.

As has been readily understood by the above descriptions, according tothe present invention, it is possible to select a camera and operate theimage-sensing direction as well as magnification ratio of the camerawhile acknowledging the currently-sensing image, taking intoconsideration of the combined image-sensible range of a plurality ofcameras and a current image-sensing range therein. The present inventionis particularly advantageous since the operation of image sensingbecomes easy when image sensing is performed by following a subjectmoving from one image-sensible range of one camera to anotherimage-sensible range of another camera. Moreover, an operator is able toeasily operate a plurality of cameras as if he/she is operating a singlecamera having a large field of view.

The present invention is not limited to the above embodiments andvarious changes and modifications can be made within the spirit andscope of the present invention. Therefore, to appraise the public of thescope of the present invention, the following claims are made.

What is claimed is:
 1. A camera control apparatus for controlling aplurality of video cameras which are controllable with respect to atleast one of panning and tilting angles, comprising: a display controldevice for displaying a first area indicative of a wide image-sensiblerange formed by combining image-sensible ranges, each of said rangesdefined by limit of at least one of panning and tilting of each of thevideo cameras, said first area exceeding a field of view of a camera andbeing formed by combining images sensed by the plurality of videocameras; a detecting device for detecting a position, which is pointedto by a user, within the first area; and a selection device forselecting a camera of the plurality of video cameras corresponding to adetecting result of said detecting device.
 2. The camera controlapparatus according to claim 1, wherein said display control devicedisplays an image sensed by the camera selected by said selectiondevice.
 3. The camera control apparatus according to claim 1, furthercomprising combining device for combining images sensed by controllingeach of the video cameras, and for displaying a wide-area image obtainedby combining the images within the first area.
 4. The camera controlapparatus according to claim 1, further comprising: control device forcontrolling at least one of panning and tilting of the video cameraselected by said selection device in accordance with the pointedposition.
 5. The camera control apparatus according to claim 1, whereinsaid display control device displays a second area indicative of a fieldof view currently image-sensed by the selected camera within the firstarea; wherein said a display position of the second area is changed soas to select a desired position within the first area.
 6. The cameracontrol apparatus according to claim 5, wherein said image-sensibleranges corresponding to each of the video cameras overlap each other,where the overlapped portion is, at least, larger than the second area.7. The camera control apparatus according to claim 5, wherein saiddisplay control device displays an image sensed by the camera selectedby said selection means, said display control device displaying theimage in the second area.
 8. The camera control apparatus according toclaim 5, wherein said video camera is also controllable with respect tomagnification ratio of image sensing.
 9. The camera control apparatusaccording to claim 8, wherein said display control device displays thesecond area in a size corresponding to a zoom value of the selectedcamera.
 10. The camera control apparatus according to claim 9, whereinsaid detecting device detects a change of the size of said second area,said control apparatus further comprising control device for, inaccordance with the position and the size of the second area detected bysaid detecting device, controlling at least one of panning and tiltingand zooming of the camera selected by said selection device.
 11. Thecamera control apparatus according to claim 5, wherein said displaycontrol device displays a partial area, surrounding said second area, ofsaid first area.
 12. The camera control apparatus according to claim 1,further comprising: control device for controlling at least one ofpanning and tilting of the video camera selected by said selectiondevice.
 13. The camera control apparatus according to claim 1, whereinthe first area comprises a seamless image formed by combining imagessensed by the plurality of video cameras.
 14. A control method of acamera control apparatus for controlling a plurality of video cameraswhich are controllable with respect to at least one of panning andtilting angles, comprising: a first display step of displaying a firstarea indicative of a wide image-sensible range formed by combiningimage-sensible ranges, each of the ranges defined by limit of at leastone of panning and tilting of each of the video cameras, said first areaexceeding a field of view of a camera and being formed by combiningimages sensed by the plurality of video cameras; a detecting step ofdetecting a designation of a desired position within the first area; anda selecting step of selecting a camera corresponding to a designatedposition in accordance with the detection result of said detecting step.15. The control method according to claim 14, wherein saidimage-sensible ranges corresponding to each of the video cameras overlapeach other, where the overlapped portion is, at least, larger than thesecond area.
 16. The control method according to claim 14, furthercomprising an image display step for displaying an image sensed by thecamera selected by said selection step.
 17. The control method accordingto claim 14, further comprising a combining step for combining imagessensed by controlling each of the video cameras and for displaying awide-area image obtained by combining the images within the first area.18. The control method according in claim 14, wherein said first displaystep displays a partial area, surrounding said second area, of saidfirst area.
 19. The control method according to claim 14, furthercomprising: a second display step of displaying a second area indicativeof a field of view currently image-sensed by the selected camera withinthe first area; wherein a display position of the second area is changedso as to select a desired position within the first area.
 20. Thecontrol method according to claim 19, further comprising: an imagedisplay step for displaying an image sensed by the camera selected bysaid selection step; wherein said image display step displays the imagein the second area.
 21. The control method according to claim 19,wherein said video camera is also controllable with respect tomagnification ratio of image sensing.
 22. The control method accordingto claim 21, wherein the second display step displays the second area ina size corresponding to a zoom value of the selected camera.
 23. Thecontrol method according to claim 22, further comprising a control stepfor, in accordance with the position and the size of said second area,controlling at least one of panning, tilting and zooming of the cameraselected by the selecting step.
 24. The control method according toclaim 19, further comprising: a control step for controlling at leastone of panning or tilting of the video camera selected by said selectingstep in accordance with the position of said second area.
 25. Thecontrol method according to claim 14, further comprising: a control stepfor controlling at least one of panning or tilting of the video cameraselected by said selecting step.
 26. A storage medium storingcomputer-readable program codes for controlling a plurality of videocameras which are controllable with respect to at least one of panningand tilting angles, comprising: a first-display-step program code fordisplaying a first area indicative of a wide image-sensible range formedby combining image-sensible ranges, each of image-sensible rangesdefined by limit of at least one of panning and tilting of each of thevideo cameras, said first area exceeding a field of view of a camera andbeing formed by combining images sensed by the plurality of videocameras; a detecting-step program code for a designation of a desiredposition within the first area; and a selecting-step program code forselecting a camera corresponding to a designated position in accordancewith the detection result of said detecting step.
 27. The storage mediumaccording to claim 26, further comprising an image-display-step programcode for displaying an image sensed by the camera selected by theselecting-step program code.
 28. The storage medium according claim 26,further comprising a combining-step program code for combining imagessensed by controlling each of the video cameras and for displaying awide-area image obtained by combining the image within the first area.29. The storage medium according to claim 26, further comprising: asecond display program code for displaying a second area indicative of afield of view currently image-sensed by the selected camera within thefirst area; wherein a display position of the second area is changed soas to select a desired position within the first area.
 30. The storagemedium according to claim 29, wherein said image-sensible rangescorresponding to each of the video cameras overlap each other, where theoverlapped portion is, at least, larger than the second area.
 31. Thestorage medium according to claim 29, further comprising animage-display-step program code for displaying the image in the secondarea, wherein said image-display-step code displays the image in thesecond area.
 32. The storage medium according to claim 29, wherein saidvideo camera is also controllable with respect to magnification ratio ofimage sensing.
 33. The storage medium according to claim 32, wherein thesecond-display step program code displays the second area in a sizecorresponding to a zoom value of the selected camera.
 34. The storagemedium according to claim 33, further comprising a control-step programcode for, in accordance with the position and the size of said secondarea, controlling at least one of panning, tilting and zooming of thecamera selected by the selecting-step program code.
 35. The storagemedium according to claim 29, further comprising: a control-step programcode for controlling at least one of panning or tilting of the videocamera selected by said selecting-step program code in accordance withthe position of said second area.
 36. The storage medium according toclaim 29, wherein said first-display-step program code displays apartial area, surrounding said second area, of said first area.
 37. Thestorage medium according to claim 26, further comprising: a control-stepprogram code for controlling at least one panning and tilting of thevideo camera selected by said selecting step program code.
 38. A cameracontrol apparatus for controlling a plurality of image sensingapparatuses, comprising: displaying unit for displaying a first areaindicative of a wide image-sensible range formed by combining imagesensible ranges, each of said ranges defined by limit of at least one ofpanning and tilting of the image sensing apparatuses, said first areaexceeding each field of view of the image sensing apparatuses and beingformed by combining images sensed by the plurality of image sensingapparatuses; and control unit for selecting an image sensing apparatusof the plurality of image sensing apparatus corresponding to a position,which is pointed to by a user, within the first area.
 39. The cameracontrol apparatus according to claim 38, wherein said displaying unitdisplays a second area indicative of a field of view currentlyimage-sensed by the selected image sensing apparatus within the firstarea.
 40. The camera control apparatus according to claim 39, whereinsaid control unit controls at least one of panning and tilting of theselected image sensing apparatus in accordance with detecting a changeof a position of said second area.
 41. The camera control apparatusaccording to claim 39, wherein said control unit controls amagnification of the selected image sensing apparatus in accordance withdetecting a change of the size of said second area.
 42. The cameracontrol apparatus according to claim 38, wherein said display unitdisplays an image sensed by said selected image sensing apparatus.
 43. Acamera control apparatus for controlling a plurality of video cameraswhich are controllable with respect to panning and tilting angles,comprising: a display control device for displaying a first areaindicative of a wide image-sensible range formed by combiningimage-sensible ranges, each of said ranges defined by limit of panningand tilting of each of the video cameras, said first area exceeding afield of view of a camera; a detecting device for detecting a position,which is pointed to by a user, within the first area; and a selectiondevice for selecting a camera of the plurality of video camerascorresponding to a detecting result of said detecting device.
 44. Thecamera control apparatus according to claim 43, wherein said displaycontrol device displays a second area indicative of a field of viewcurrently image-sensed by the selected camera within the first area;wherein a display position of the second area is changed so as to selecta desired position within the first area.
 45. A control method of acamera control apparatus for controlling a plurality of video cameraswhich are controllable with respect to panning and tilting angles,comprising: a first display step of displaying a first area indicativeof a wide image-sensible range formed by combining image-sensibleranges, each of the ranges defined by limit of panning and tilting ofeach of the video cameras, said first area exceeding a field of view ofa camera; a detecting step of detecting a designation of a desiredposition within the first area; and a selecting step of selecting acamera corresponding to a designated position in accordance with thedetection result of said detecting step.
 46. The control methodaccording to claim 45, further comprising: a second display step ofdisplaying a second area indicative of a field of view currentlyimage-sensed by the selected camera within the first area; wherein adisplay position of the second area is changed so as to select a desiredposition within the first area.
 47. A storage medium storingcomputer-readable program codes for controlling a plurality of videocameras which are controllable with respect to panning and tiltingangles, comprising: a first-display-step program code for displaying afirst area indicative of a wide image-sensible range formed by combiningimage-sensible ranges, each of image-sensible ranges defined by limit ofpanning and tilting of each of the video cameras, said first areaexceeding a field of view of a camera; a detecting-step program code fora designation of a desired position within the first area; and aselecting-step program code for selecting a camera corresponding to adesignated position in accordance with the detection result of saiddetecting step.
 48. The storage medium according to claim 47, furthercomprising: a second display program code for displaying a second areaindicative of a field of view currently image-sensed by the selectedcamera within the first area; wherein a display position of the secondarea is changed so as to select a desired position within the firstarea.
 49. A camera control apparatus for a controlling a plurality ofimage sensing apparatuses which are controllable with respect to panningand tilting angles, comprising: displaying unit for displaying a firstarea indicative of a wide image-sensible range formed by combining imagesensible ranges, each of said ranges defined by limit of panning andtilting of the image sensing apparatuses, said first area exceeding eachfield of view of the image sensing apparatuses; and controlling unit forselecting an image sensing apparatus of the plurality of image sensingapparatuses corresponding to a position, which is pointed to by a user,within the first area.
 50. The camera control apparatus according toclaim 49, wherein said displaying unit displays a second area indicativeof a field of view currently image-sensed by the selected image sensingapparatus within the first area.